using System.Collections.Concurrent;
using System.Diagnostics;
using System.Globalization;

namespace StellaOps.ElkSharp;

internal static partial class ElkEdgeRouterIterative
{
    internal static ElkRoutedEdge[] BuildFinalBoundarySlotCandidate(
        ElkRoutedEdge[] edges,
        ElkPositionedNode[] nodes,
        ElkLayoutDirection direction,
        double minLineClearance,
        IReadOnlyCollection<string>? restrictedEdgeIds = null,
        bool allowLateRestabilizedClosure = true)
    {
        var focusEdgeIds = restrictedEdgeIds?.Count > 0
            ? restrictedEdgeIds
            : edges
                .Select(edge => edge.Id)
                .OrderBy(edgeId => edgeId, StringComparer.Ordinal)
                .ToArray();
        var useLeanRestrictedBoundarySlotPass =
            restrictedEdgeIds?.Count > 0
            && (!allowLateRestabilizedClosure
                || restrictedEdgeIds.Count <= 2);
        var useUltraLeanRestrictedBoundarySlotPass =
            restrictedEdgeIds?.Count > 0
            && restrictedEdgeIds.Count <= MaxWinnerPolishBatchedRootEdges + 1;
        ElkLayoutDiagnostics.LogProgress(
            $"Boundary-slot candidate start: focus={focusEdgeIds.Count} allowLateRestabilizedClosure={allowLateRestabilizedClosure}");

        var best = edges;
        var candidate = ElkEdgePostProcessor.SnapBoundarySlotAssignments(
            edges,
            nodes,
            minLineClearance,
            restrictedEdgeIds,
            enforceAllNodeEndpoints: true);
        best = ChoosePreferredBoundarySlotRepairLayout(best, candidate, nodes);
        ElkLayoutDiagnostics.LogProgress("Boundary-slot candidate after initial snap");
        var terminalClosureCandidate = useLeanRestrictedBoundarySlotPass
            ? ApplyHybridTerminalRuleCleanupRound(
                candidate,
                nodes,
                direction,
                minLineClearance,
                restrictedEdgeIds)
            : CloseRemainingTerminalViolations(
                candidate,
                nodes,
                direction,
                minLineClearance,
                restrictedEdgeIds);
        candidate = ChoosePreferredBoundarySlotRepairLayout(candidate, terminalClosureCandidate, nodes);
        best = ChoosePreferredBoundarySlotRepairLayout(best, candidate, nodes);
        ElkLayoutDiagnostics.LogProgress("Boundary-slot candidate after terminal closure");
        if (focusEdgeIds.Count > 0)
        {
            candidate = ElkEdgePostProcessor.SeparateMixedNodeFaceLaneConflicts(
                candidate,
                nodes,
                minLineClearance,
                focusEdgeIds);
            candidate = ElkEdgePostProcessor.SeparateSharedLaneConflicts(
                candidate,
                nodes,
                minLineClearance,
                focusEdgeIds);
            best = ChoosePreferredBoundarySlotRepairLayout(best, candidate, nodes);
            ElkLayoutDiagnostics.LogProgress("Boundary-slot candidate after face/shared-lane separation");
        }

        candidate = ClampBelowGraphEdges(candidate, nodes, restrictedEdgeIds);
        candidate = ElkEdgePostProcessor.NormalizeBoundaryAngles(candidate, nodes);
        candidate = ElkEdgePostProcessor.NormalizeSourceExitAngles(candidate, nodes);
        candidate = ElkEdgePostProcessor.SnapBoundarySlotAssignments(
            candidate,
            nodes,
            minLineClearance,
            restrictedEdgeIds,
            enforceAllNodeEndpoints: true);
        best = ChoosePreferredBoundarySlotRepairLayout(best, candidate, nodes);
        ElkLayoutDiagnostics.LogProgress("Boundary-slot candidate after normalization snap");
        if (useUltraLeanRestrictedBoundarySlotPass)
        {
            ElkLayoutDiagnostics.LogProgress("Boundary-slot candidate complete (ultra-lean restricted path)");
            return ChoosePreferredBoundarySlotRepairLayout(best, candidate, nodes);
        }
        candidate = ApplyPostSlotDetourClosure(candidate, nodes, minLineClearance, restrictedEdgeIds);
        best = ChoosePreferredBoundarySlotRepairLayout(best, candidate, nodes);
        ElkLayoutDiagnostics.LogProgress("Boundary-slot candidate after detour closure");
        candidate = ElkEdgePostProcessor.SnapBoundarySlotAssignments(
            candidate,
            nodes,
            minLineClearance,
            restrictedEdgeIds,
            enforceAllNodeEndpoints: true);
        best = ChoosePreferredBoundarySlotRepairLayout(best, candidate, nodes);
        ElkLayoutDiagnostics.LogProgress("Boundary-slot candidate after detour snap");
        if (useLeanRestrictedBoundarySlotPass)
        {
            ElkLayoutDiagnostics.LogProgress("Boundary-slot candidate complete (lean restricted path)");
            return ChoosePreferredBoundarySlotRepairLayout(best, candidate, nodes);
        }

        if (restrictedEdgeIds?.Count > 0)
        {
            candidate = ChoosePreferredBoundarySlotRepairLayout(
                candidate,
                CloseRemainingTerminalViolations(candidate, nodes, direction, minLineClearance, restrictedEdgeIds),
                nodes);
            best = ChoosePreferredBoundarySlotRepairLayout(best, candidate, nodes);
            candidate = ElkEdgePostProcessor.SnapBoundarySlotAssignments(
                candidate,
                nodes,
                minLineClearance,
                restrictedEdgeIds,
                enforceAllNodeEndpoints: true);
            best = ChoosePreferredBoundarySlotRepairLayout(best, candidate, nodes);
            ElkLayoutDiagnostics.LogProgress("Boundary-slot candidate after restricted terminal recheck");
        }

        candidate = ApplyLateBoundarySlotRestabilization(
            candidate,
            nodes,
            minLineClearance,
            focusEdgeIds);
        best = ChoosePreferredBoundarySlotRepairLayout(best, candidate, nodes);
        ElkLayoutDiagnostics.LogProgress("Boundary-slot candidate after late restabilization");
        candidate = ChoosePreferredBoundarySlotRepairLayout(
            candidate,
            ElkEdgePostProcessor.SnapBoundarySlotAssignments(
                candidate,
                nodes,
                minLineClearance,
                    restrictedEdgeIds,
                    enforceAllNodeEndpoints: true),
                nodes);
        best = ChoosePreferredBoundarySlotRepairLayout(best, candidate, nodes);
        ElkLayoutDiagnostics.LogProgress("Boundary-slot candidate after late restabilization snap");
        if (focusEdgeIds.Count > 0)
        {
            var lateHardRuleCandidate = ApplyAggressiveSharedLaneClosure(
                candidate,
                nodes,
                direction,
                minLineClearance,
                focusEdgeIds);
            lateHardRuleCandidate = ElkEdgePostProcessor.SnapBoundarySlotAssignments(
                lateHardRuleCandidate,
                nodes,
                minLineClearance,
                restrictedEdgeIds,
                enforceAllNodeEndpoints: true);
            candidate = ChoosePreferredHardRuleLayout(candidate, lateHardRuleCandidate, nodes);
            candidate = ChoosePreferredBoundarySlotRepairLayout(
                candidate,
                ElkEdgePostProcessor.SnapBoundarySlotAssignments(
                    candidate,
                    nodes,
                    minLineClearance,
                    restrictedEdgeIds,
                    enforceAllNodeEndpoints: true),
                nodes);
            best = ChoosePreferredBoundarySlotRepairLayout(best, candidate, nodes);
            ElkLayoutDiagnostics.LogProgress("Boundary-slot candidate after late hard-rule closure");
        }
        if (focusEdgeIds.Count > 0
            && (ElkEdgeRoutingScoring.CountBoundarySlotViolations(candidate, nodes) > 0
                || ElkEdgeRoutingScoring.CountGatewaySourceExitViolations(candidate, nodes) > 0))
        {
            var lateClosureCandidate = ApplyLateFocusedBoundarySlotClosure(
                candidate,
                nodes,
                direction,
                minLineClearance,
                focusEdgeIds,
                restrictedEdgeIds);
            candidate = ChoosePreferredBoundarySlotRepairLayout(candidate, lateClosureCandidate, nodes);
            candidate = ChoosePreferredBoundarySlotRepairLayout(
                candidate,
                ElkEdgePostProcessor.SnapBoundarySlotAssignments(
                    candidate,
                    nodes,
                    minLineClearance,
                    restrictedEdgeIds,
                    enforceAllNodeEndpoints: true),
                nodes);
            best = ChoosePreferredBoundarySlotRepairLayout(best, candidate, nodes);
            ElkLayoutDiagnostics.LogProgress("Boundary-slot candidate after focused late closure");
        }

        if (allowLateRestabilizedClosure
            && focusEdgeIds.Count > 0
            && focusEdgeIds.Count <= MaxLateRestabilizedClosureFocusEdges)
        {
            var stagedLateRestabilizedCandidate = ElkEdgePostProcessor.SnapBoundarySlotAssignments(
                edges,
                nodes,
                minLineClearance,
                restrictedEdgeIds,
                enforceAllNodeEndpoints: true);
            stagedLateRestabilizedCandidate = BuildFinalRestabilizedCandidate(
                stagedLateRestabilizedCandidate,
                nodes,
                direction,
                minLineClearance,
                restrictedEdgeIds);
            stagedLateRestabilizedCandidate = ChoosePreferredBoundarySlotRepairLayout(
                stagedLateRestabilizedCandidate,
                ElkEdgePostProcessor.SnapBoundarySlotAssignments(
                    stagedLateRestabilizedCandidate,
                    nodes,
                    minLineClearance,
                    restrictedEdgeIds,
                    enforceAllNodeEndpoints: true),
                nodes);
            candidate = ChoosePreferredBoundarySlotRepairLayout(candidate, stagedLateRestabilizedCandidate, nodes);
            best = ChoosePreferredBoundarySlotRepairLayout(best, candidate, nodes);
            ElkLayoutDiagnostics.LogProgress("Boundary-slot candidate after staged late restabilized closure");
        }

        ElkLayoutDiagnostics.LogProgress("Boundary-slot candidate complete");
        return ChoosePreferredBoundarySlotRepairLayout(best, candidate, nodes);
    }

}